d10 Chess

by Bruce Leban

Roll a ten sided die (d10) every turn to determine which pieces may be moved. All rules of standard chess apply except as specifically noted here.

Rules

1. Setup. The game starts with the standard chess arrangement on an 8x8 board.

2. Turns. Each turn consists of the following two steps:

Roll the die.
Move one of the allowed pieces listed in the table below. If the roll is a 10 or 0, you can move any piece except a pawn. (Some ten sided dice have a 0 and some have a 10. Treat these interchangeably.) Otherwise, round the number on the die up to 1, 3, 5 or 9 and move any piece whose value is less than that value using these equivalents: P = 1, N = 3, B= 3, R = 5, Q = 9, K = 0.

1
2 3
4 5
6 7 8 9
10 / 0

3. Winning. A player wins by capturing the opponents king or by capturing all of the opponents pieces except the king. There is no checkmate. If one player captures all of the opponents pieces except the king, the opponent is allowed to one more move. If only the two kings are left, the game is a draw.

4. Check. A king may remain in check after a move and a player may even move the king into check. In casual play, a player who moves the king into check or does not move out of check should be given a warning and the chance to make a different move.

5. Castling. Castling is considered as a rook move (i.e., you can only castle if you roll a 4 or higher). Kings may castle through check.

6. Promoting. When a pawn moves to the last rank, it must be promoted. It may only be promoted to a piece that could have moved on that turn (i.e., if the roll is a 2 or 3, the pawn may only promote to a bishop or knight and a pawn may not move to the last rank on a roll of 1).

7. Must move. A player must move if able to do so, even if disadvantageous.

8. Can't move. If the player cannot move, then the turn is lost (i.e., not a stalemate).

9. Touch move. If playing with "touch move" rules, and a player touches or moves a piece before rolling the die, they must roll the die and move that piece or make that move, if allowed by the die roll. If that piece may not be moved, they may move any other piece.

Notes

The mobility of the pieces is inversely related to their strength, which means that the pieces are much more evenly matched. For example, if a bishop threatens a queen, it has about a 47% chance of being able to take the queen before the queen can move away or take the bishop. (That is, rolling 2+ to move the bishop again before the opponent rolls 6+ to move the queen.)

If the king is in check, the best move is to lower the probability that the king can be captured, which may involve remaining in check and playing the odds. In d10 Chess, the king can actually take the opponent's queen (about half the time, that is).